1. Field of the Invention
The present invention relates to a mobile communication system constituted by a control station, a base station, and a mobile station, and the control station provided in this mobile communication system.
2. Related Background Art
In a conventional mobile communication system constituted by a control station, a base station, and a mobile station, various types of multimedia signal, from voice communication to high-speed packet communication, can be transmitted in an integrated manner, and thus a plurality of services, also known as a multi-call service, can be provided simultaneously (for example, FOMA (registered trademark): freedom of mobile multimedia access). A mobile communication system based on FOMA is known as a third generation mobile communication system. In order to realize various services according to the needs of a user, this mobile communication system employs a system architecture according to which an optimum transmission speed is determined by the control station in comprehensive consideration of the content of the service request, the packet transmission speed, the functional capability of the terminal, the network condition, and so on, whereupon a dedicated channel corresponding to the determined optimum transmission speed is selected and allocated.
In conventional mobile communication systems, a technique relating to changeover of the dedicated channel during communication is known. According to this technique, a transition is made to a radio channel having a different transmission capability in accordance with the amount of information that is transferred over the radio channel that is currently performing communication (see Patent Document 1, for example).
[Patent Document 1] JP-A-2002-271847